T he cumulative i mpact of these dams has not been examined by any agency so far. Preliminary estimates show that a total of 20,224 hectares of land — of which nearly 7,000 hectares is forest and protected area land — will be submerged and almost a lakh people, mostly tribals, displaced, the report said.

Also, large swathes of land that will be submerged lie in the Ecologically Sensitive Zone (ESZ) 1, according to both the Western Ghats Ecology Expert Panel (WGEEP), chaired by environmentalist Madhav Gadgil, as well as the Kasturirangan Committee report on Western Ghats. HT has a copy of the report, which will be released on Wednesday.

“This destruction is unjustified because Mumbai and MMR have not explored other options of sourcing water. The demand projections are grossly exaggerated, and nearly 33% of water supplied to Mumbai is unaccounted for,” said Himanshu Thakkar, water policy analyst and co-author of the report.

However, Mumbai needs 4,200 million litres of water a day, accounting for leakages, said Rajiv Jalota, additional commissioner, BMC, but added that the civic body has started a water distribution improvement programme to rationalise usage. See page 7

Mumbai could plug leakages in its water supply system, two of the dams could have been avoided

MUMBAI: Mumbai and the rest of the Mumbai Metropolitan Region (MMR) have over-estimated their water requirement for domestic and industrial purposes, but have not conducted any option assessment studies which could substantially reduce – or even obliterate – the need for dams in the Western Ghats.

Without thorough option assessment studies, the rivers in the Western Ghats are being seen as a ready source of water supply which is very damaging to the ecology and people there, states the report prepared by the South Asia Network on Dams, Rivers and People, to be released today.

The options assessment studies could include a range of options – from groundwater re-charging and rainwater harvesting to water management techniques and reusing treated sewage water for selective purposes. Of the 12 dams, nine are in Thane district, two in Raigad and one in Nashik district.

However, the simplest and highimpact option is to plug leakages in the system, it adds. Of the nearly 3,500 million litres a day (mld) water supplied to Mumbai, nearly 33 per cent “is unaccounted for”, the report points out. If accounted for, two – or even three – of the proposed dams need not have been constructed, said Himanshu Thakkar, water policy analyst and co-author of the report.

Moreover, the cumulative impacts of all these projects on the area have not been studied, points out Thakkar.

The reliance on these dams also runs contrary to the recommendation of the Working Group (Water) for the 12th Five Year Plan 2012-17 which states: “…Therefore, cities must only get funds for water projects when they have accounted for water supply from all local bodies”.

The report calls into question the water demand projections for Mumbai. The Madhav Chitale Committee, in 1999, estimated the population to be nearly 14 million in the Brihanmumbai Municipal Corporation limits and pegged demand at 4,240 million litres a day (mld), but the Census Survey 2011 showed the population to be 12.4 million which brings down the water demand by approximately 320 mld, states the report.

“The Chitale Committee figures are off the mark, so where’s the urgency to develop new dams,” asks Thakkar. A review and new projections could mean that a few dams need not be constructed.

However, the BMC disagrees. “The estimated figure of 4200 mld has been calculated after considering the unaccounted for water and water loss. There is certainly a requirement of more than 4000 mld water for the city,” said Rajiv Jalota, additional municipal commissioner.